"The general feeling that SkyOS gives is... Simply great! A lot of work done under the hood seems to be paying back with a solid, responsive operating system. It scales very nicely, opening up a lot of OpenGL demos and other applications at once doesn't seem to affect stability, however it is currently very resource hungry (600MB RAM usage and up isn't anything strange while using Firefox, Gaim and having a few more apps open). Let us not forget that this is a debug build. It is completely usable and boots blazingly fast (~15 seconds from GRUB to desktop) though."My take: The best change? The new versioning scheme. Really.

Yeah, syllable is open source, but GPL.
that means they can legally port linux drivers etc.
but still... has the same licencing restrictions as linux.
I prefer a more open licence like zlib or mit.
take a look at the haiku-os project, open source beos clone.
and there are lots of os'es at www.altos.tk